A sprinter's velocity is read from a video every second: In which second is her acceleration…

Step 1. Accelerations. $4.5\ \text{m/s}^2$, $3.5\ \text{m/s}^2$, $1.5\ \text{m/s}^2$, $0\ \text{m/s}^2$ and $-0.5\ \text{m/s}^2$ in the five seconds. The greatest is $4.5\ \text{m/s}^2$, in the first second.

Step 2. Strips. $2.25\ \text{m} + 6.25\ \text{m} + 8.75\ \text{m} + 9.5\ \text{m} + 9.25\ \text{m} = 36\ \text{m}$.